The objectives of this proposal are to 1) map the functional organization of human primary motor cortex for both volitional and imagined movements and 2) determine the relationship between primary motor cortex maps obtained by functional magnetic resonance imaging (fMRI), optical;, intrinsic signaling (0IS) and direct cortical stimulation (DCS) in a group of tumor patients undergoing awake craniotomy. The results of this work will lead to a better understanding of the, physiology of the human motor system as well as establish the validity of new non-invasive methods to map critical human brain functions in patients preoperatively. Normal subjects will be studied first to determine whether human motor cortex is characterized by overlapping representations of distal arm and hand movements. Individual digit and wrist movements will be investigated using the fMRI blood oxygen level dependent (BOLD) technique. FMRI will also be used to determine whether imagined movements can produce reliable activations in primary motor cortex, an issue of practical importance since this would minimize fMRI artifacts associated with real movements. Once developed and tested in controls, these motor paradigms will be used as part of a presurgical fMRI protocol to map primary motor cortex in a group of brain tumor patients scheduled for awake craniotomy due to a clinical need for intraoperative language mapping. After language mapping is completed, OIS will be used to measure cortical activations produced by volitional movements. This will be followed by traditional motor mapping using bipolar electrode DCS with careful recording and photography of the results. Motor maps obtained with fMRI, OIS and DCS will be compared using state-of-the-art image processing tools. This is a unique opportunity to study the physiology of human primary motor cortical control of electrically evoked, volitional and imagined movements, using the traditional as well as the most modern mapping techniques. This work will establish the appropriate clinical role of fMRI mapping of upper extremity primary motor cortex, a role that could later be expanded to lower extremity cortex if imagined movement paradigms prove successful. Finally, a more complete understanding of the organization of human primary motor cortex will lay a foundation for future investigations of motor recovery.